hydrofoils are coming along

[Jeff Walkowiak]

Re: hydrofoils are coming along

hy?dro?foil (hī'drə-foil') Pronunciation Key
n.
A winglike structure attached to the hull of a boat that raises all or part of the hull out of the water when the boat is moving forward, thus reducing drag.
A boat equipped with hydrofoils.

 

[QC]

Re: hydrofoils are coming along

Yeah, and I understand why you built them parallel to the pontoons themselves. Just curious about the hydrodynamics . . . Do you have good data pre-foil? Speed, fuel etc.?

 

[Jeff Walkowiak]

Re: hydrofoils are coming along

yea I use the most common system known to man even the cavemen used it,, It's called the W. A. G. system.
By the way N. A. S. A. uses the same system quite often. They also have a motto,, we learn from our mistakes. Although I don't use the lowest bidder.

 

[Jeff Walkowiak]

Re: hydrofoils are coming along

front deflectors

I also removed the backs of the front seats, made new bases to accommodate the larger opening, and made pads for the rails, this eliminated 40 lbs of weight from the front of the boat.

I also moved the both batteries from the rear deck and put them under one of the seats to balance out the weight better.

and I created more buoyancies in the back by making a compartment in the engine tray and filling it with foam.

 

[rickdb1boat]

Re: hydrofoils are coming along

Your overall design reminds me of Tap Fins or lifting strakes, only instead of being welded to the logs, they are part of the structure and are much lower to the water. Very interesting project and I look forward to the test results when finished.

 

[Jeff Walkowiak]

Re: hydrofoils are coming along

I saw those and liked the idea but wondered if the pontoons were heavier material than regular ones , plus I would not even try to do that to old pontoons for fear of it causing metal fatigue or pin holes etc,, I don't do all that well with thin aluminum. This is actually my first real project welding aluminum, I usually do stainless, so I was a bit apprehensive at first ,but after I welded the first 2, 8 foot lengths together, and used my old aluminum grinding trick"bees wax' to smooth them out ,I actually placed them on milk crates and jumped up and down on the welded area to be sure it was a solid weld,, and it was stronger than death.
You would have laughed if you saw how I put the bends in the rails after I welded the pieces together, a little ingenuity goes a long way.

 

[sschefer]

Re: hydrofoils are coming along

Jeff, I'm joining this a little late but what I'm seeing is that your intention is to tranform a displacement hull into a planeing hull. You're not really trying to lift the sponsons out of the water you just want to add enough lift to allow them to achieve plane.

With Hydrodynamic theory aplied the maxium speed of a displacement vessel is achieved when the bow wake reaches the stern. The length of the vessel is critical to achievieving the speed you need to generate enough lift. If the boat is long enough and the foils displace surface area equal to approximately 1/2 that of the sponson you will achieve lift and plane before the bow wake reaches the stern.


If you get lift with a 70, slap a 200 on it and blow bass boats away...!!!

Yee Haw ! Hold on to the bimini Margret we're hitting Mach I.

 

[Tacklewasher]

Re: hydrofoils are coming along

yes the whole state was cold this morning. wish the Canadian, would close the freezer door. i now can see what the idea is behind the foils.

I'm just trying to figure out what I feel like having for lunch.

 

[Jeff Walkowiak]

Re: hydrofoils are coming along

I went out this morning for my newspaper and my skies ,cars etc were all covered in ice, I hate that stuff.

 

[Jeff Walkowiak]

Re: hydrofoils are coming along

closed in the center under the boat ,,

 

[wishihad]

Re: hydrofoils are coming along

Wow, very interesting! The best of luck to you! Please keep us posted!!
Sure is a good thing I don't have welder!

 

[Jeff Walkowiak]

Re: hydrofoils are coming along

I plan on giving it a run tomorrow,, water is still pretty cold , high 50's but it warmed up a little today,,plus I like going during the week,, since the ramps are quiet and there is less boat traffic to deal with.

 

[Jeff Walkowiak]

Re: hydrofoils are coming along

Well I tried it and it was INTERESTING,, although a bit disappointing,, the boat handled and rode really great,, but the angle of attack up in the front of the foils is all wrong and is actually plowing water and slowing the boat rather than making it go faster.
SO now I have to change the front to solve that problem,, and then try it again.

 

[wishihad]

Re: hydrofoils are coming along

Bummer. Sorry!
Hopefully redoing the front will fix it!

 

[tashasdaddy]

Re: hydrofoils are coming along

try and try again, makes perfect.

 

[Jeff Walkowiak]

Re: hydrofoils are coming along

Still working on this,, 8 hours a day since I tried it out Monday,, I believe I was trying to do way too much with a 70 hp engine.
I had to totally disassemble the parts and start over, since I thread locked all the bolts I needed to heat each one to remove them,, really slow going I might add.
But after spending 3 weeks total, crouched under this boat, I'm getting to the point that I'm used to it .

 

[Jeff Walkowiak]

Re: hydrofoils are coming along

Final result on this project was I raised the foils from 17 inches below the floor joists to only 8 inches below the joists,, changed the configuration from 2 long foils to 4 shorter foils with a lot less angle in the front.
I only gained about 1/2 mph on the top end, 200 rpm on the engine, I do have a lot less turbulence in the rear of the boat.
But what I did notice was a huge difference in the ride and some serious handling improvement, it handles rough water way better and will do a 180 at w o t on a dime,, steers like a dream at idle,, funny because I was not trying to make it steer better, but it takes waves and rough water like a dream and I don't get water splashing up in the front when I cut a boat wake at an angle like I used to .
Also the bed liner caper worked like a dream to close off the joists,,I used some stainless self tapping screws and flat washers to attach it to the joists,, I still need to find more liners to close in the sides, but hitting big waves was so smooth with just the center covered . Previously it was like hitting the brakes when a wave went under the boat

 

[coolguy147]

Re: hydrofoils are coming along

next thing to do is upgrade motor maybe a 135? or 150 or even more!!

 

[Jeff Walkowiak]

Re: hydrofoils are coming along

I doubt I will be doing any more major tinkering with this boat for a while, I put in 2 weeks doing the first mod and that would have been awesome if I had a 150 hp engine,, and another 40 hours redoing the entire thing.
I am satisfied that I gave it my best shot, and I don't have any complaint with the way it is now, I basically use it for fishing and it's an awesome fishing boat, and I can drive it wherever I need to go. It will not nose dive in a wave like it did before I made the foils, that alone is worth the effort,, and it's fun to do hard turns,, the boat actually carves and tilts when you turn it fast. And lining it up to drive it on the trailer is a piece of cake now.

 

[SoulWinner]

Re: hydrofoils are coming along

next thing to do is upgrade motor maybe a 135? or 150 or even more!!

Maybe a trio of 250's?